The present invention relates generally to locking, adjustment-facilitating mechanisms for steering columns and, more specifically, to systems and methods for stabilizing a steering column assembly while facilitating adjustments thereof.
A steering column lock includes locking features that selectively prevent or facilitate adjustments to the positioning and orientation of the steering column. In a locked state, a steering column lock prevents changes or adjustments to the position and/or orientation of the steering column in one or more directions relative to a structure of a vehicle. In an unlocked state, a steering column lock facilitates adjustments of the steering column in one or more directions, such as a telescoping direction oriented along a longitudinal direction of the steering column or in a raking direction oriented transversely to the longitudinal direction of the steering column.
An adjustable steering column assembly is configured to facilitate adjustment of the steering column in a plane (i.e., in one or two directions lying in an adjustment plane). Often, the adjustment plane is oriented vertically, but other orientations of the adjustment plane, such as horizontal or other intermediate orientations are also possible. A steering column lock may function in its locking mode by imposing a compressive load upon the steering column in a direction that includes at least a component that is oriented transversely to the adjustment plane. Put another way, the direction of the compressive load is oriented at an angle (e.g., a 90 degree angle, i.e., transversely) relatively to the adjustment plane. Therefore, when the steering column lock is functioning in its locking mode, the steering column lock tends to restrain movement of the steering column not only in the adjustment plane, but also in the direction that intersects (e.g., is perpendicular to) the adjustment plane, thereby defining a non-adjustment direction). For example, in a steering column assembly configured for adjustment in a vertically oriented plane, when the steering column lock is functioning in its locking mode, the steering column lock tends to restrain movement of the steering column in the horizontal (i.e., lateral) direction.
When the steering column lock is functioning in its adjustment-facilitating mode, however, the steering column lock no longer restrains movement of the steering column in the non-adjustment direction. Accordingly, upon transition of the steering column lock from the locking mode to the adjustment-facilitating mode, movement of the steering column in the non-adjustment direction may occur. Unfortunately, while a vehicle operator may anticipate that transitioning the steering column lock from the locking mode to the adjustment-facilitating mode might result in movement of the steering column within the adjustment plane, the vehicle operator may be surprised by movement of the steering column in the non-adjustment direction. In some situations, the unrestrained steering column may be motivated to move in the non-adjustment direction by forces inherent in the steering column system, by gravitational forces, by forces imposed on the steering column assembly by the operator, or by acceleration forces associated with movement of the vehicle.
In some steering column assemblies, the transition from the locking mode to the adjustment-facilitating mode is accomplished via a manually operated mechanical actuator, such as a lever arm. In other steering column assemblies, however, the transition may be accomplished automatically, such as through an electro-mechanical or electromagnetic apparatus providing for very fast transition between the locking mode to the adjustment-facilitating mode. In such quickly transitioning systems, the movement of the steering column may be sudden.
Accordingly, it is desirable to provide a selectively locking and adjustment-facilitating mechanism for a steering column assembly that enables the steering column to be stabilized in a non-adjustment direction while facilitating adjustment of the steering column in the adjustment plane.